Determination of culture coefficient of mombasa grass managed in different seasons of the year in mineiro semiarid

Abstract

The objective of this study was to evaluate crop coefficient (kc), dry matter yield (PMS) and water use efficiency of mombaça grass (Panicum maximum Jacq. cv Mombasa) managed at different seasons of the year. Four management phases (I, II, III and IV) characterized by plant heights based on mombaça grass phenology corresponding to the first phase (45 to 56 cm-start of regrowth) based on light interception of 95% were evaluated, following a completely randomized design with five repetitions. The grass was managed under cuts in drainage lysimeters. The cuts were made when the grass reached 90 cm height leaving a residue of 45 cm. The PMS in summer, autumn and winter / spring was 9,994, 8,261 and 10,705 kg.ha-1, respectively. Water consumption in summer, autumn and winter / spring was 697, 396 and 1,711 mm, respectively, resulting in an efficiency of 14.28, 20.88 and 6.26 kg.ha-1.mm-1, respectively. The crop coefficient of mombaça grass ranged from 0.79 to 1.25 in summer and autumn and from 0.62 to 1.06 in winter/spring.